1. Field of Invention
The invention is directed to an image module mounting structure that is used for mounting an image module to an imaging device. In particular, the invention relates to an imaging module mounting structure that includes a pair of pivot block devices capable of flexing to compensate for photoreceptor run out.
2. Description of Related Art
Many different types of imaging devices are available in the marketplace. One type of imaging device uses a drum-type photoreceptor and an imaging module that is mounted in close proximity to the drum-type photoreceptor. The imaging module includes the charging and exposure subsystems. Typically, the charging subsystem is a corona generating device such as a scorotron charging device and the exposure subsystem is a conventional light emitting diode imaging bar.
The imaging module is mounted to an imaging module mounting structure. Typically, the imaging module mounting structure is pivotably mounted to a support within the imaging device. The imaging module mounting structure includes a pair of cam followers that are designed to be in contact with opposite ends of the drum-type photoreceptor. However, although the drum-type photoreceptor appears perfectly cylindrical to a human eye, the cross sectional configuration of the photoreceptor is eccentric which is commonly referred to as "photoreceptor run out". Thus, as the photoreceptor rotates about its axis of rotation, the surface of the photoreceptor rises and falls relative to a perfectly circular shape. Generally, photoreceptor run out ranges between plus and minus 0.006 inches.
Photoreceptor run out causes one of the pair of cam followers to intermittently lose contact with the photoreceptor as it rotates. As one of the pair of cam followers loses contact with the surface of the photoreceptor, the focal spacing of the image bar relative to the photoreceptor varies. Also, the relationship of the corona generating device relative to the photoreceptor also becomes distorted. Variable focal spacing and uneven spacing of the corona charging device relative to the photoreceptor result in poor imaging.
Also, it is desirable to maintain a predetermined temperature of the imaging bar. Unstable imaging results occur when the critical temperature of the imaging bar cannot be maintained. Also, without sufficient airflow through the imaging module, the corona charging device can produce ozone which also can be detrimental to the imaging process.